October 1, 2019

Why Lead solder is not allowed on gas systems in UK

There has been much debate recently on the use of Lead Solder for heating pipes and non-potable supplies which include gas. This paper is the first in a series to be published by as part of the World Health Organisation ‘International Lead Poisoning Prevention Week 2019 #ILPPW2019’

A range of organisations, professionals and occupational workers have made comments on social media – these include a water regulations advisory scheme, a Professional Heating Engineering body, a Trade Association, Plumbers, Gas Safe Register Engineers, Teaching professionals and Training centres who argue that Lead Solder is allowed on heating and gas distribution systems in buildings. This article reviews the current regulations and interprets the statutory instruments on behalf of professional plumbers, gas engineers and the UK public to clarify the matter. 

The May/June (2019: 30) issue of the Chartered Institute of Plumbing and Heating Engineering (CIPHE) Journal P&H Engineering stated (p.30-31 here):

The Water Supply (Water Fittings) Regulations prohibit the use of Lead on any part of a wholesome water system. While lead is allowed on closed-circuit heating and gas systems, any heating system using lead is legally required to be fitted with adequate backflow protection to ensure the complete safety of the drinking water supply. (my emphasis in bold)

For the purposes of this short paper, the argument presented is in regard to the statement that CIPHE make about lead solder being allowed on gas systems. 

This paper argues that the use of lead solder or lead alloys to “make” or joint fittings is not “allowed”, “legal” or “safe” on any “gas system” in the UK.


The statutory instrument Number 2451 is a Health and Safety document regarding The Gas Safety (Installation and Use) Regulations (GSIUR) 1998 (here), which is still in use in 2019. 

Gas Safe Register Engineers, Teachers and Training centres are duty bound to comply with these regulations. It must be noted that Training Centres and Further Education Colleges are not exempt in any way from these regulations – there are no concessions to have installations or training rigs in Colleges which are a danger to any person (section 5.3 GSIUR 1998).

Section 5 of the GSIUR (1998) deals with Materials and Workmanship and for the purposes of this argument, it is shown below:

Materials and Workmanship (extract from GSIUR 1998)

5. (1) No person shall install a gas fitting unless every part of it is of good construction and sound material, of adequate strength and size to secure safety and of a type appropriate for the gas with which it is to be used.

(2) Without prejudice to the generality of paragraph (1) above, no person shall install in a building any pipe or fitting for use in the supply which is – 

(a) Made of lead or lead alloy; or

(b) Made of a non-metallic substance unless it is –

(i) a pipe connected to a readily movable gas appliance designed for use without a flue; or (ii) a pipe entering the building and that part of it within the building is placed inside a metallic sheath which is so constructed and installed as to prevent, so far as is reasonable practicable, the escape of gas into the building if the pipe should fail.

(3) No person shall carry out any work in relation to a gas fitting  or gas storage otherwise than in accordance with appropriate standards and in such a way as to prevent danger to any person.

The Argument

This paper presents three lines of argument against lead solder being “allowed” on gas distributions systems or pipes in buildings in the UK:

The first line of argument: Nowhere in the GSIUR 1998 does it say that lead solder is ‘allowed’ or legal on gas pipes, fittings, joints or distribution systems in buildings.

The second line of argument: The prohibited use of Lead Solder (alloy) in the jointing or construction of any gas is implied in GSIUR (1998) section (2):

No person shall install in a building any pipe or fitting for use in the supply which is (a) Made of lead or lead alloy. 

For example – section 5.(1) above states:

No person shall install a gas fitting unless every part of it is of good construction and sound material, of adequate strength and size to secure safety.

This means that a copper end-feed fitting is legal but in order to joint copper pipe, the fitting alone would not be secure – it would need solder to make it secure. Therefore, solder is an essential part of the fitting in order to make a sound method of making joints on end-feed fittings to copper gas pipes, in a safe and secure way. 

When the GSIUR 1998 makes reference to a fitting, and if the fitting used is an end-feed type, it arguably includes the solder alloy used to make the joint safe and secure – Therefore, fittings jointed with lead solder alloy are not legal gas fittings for copper gas pipes because the joint or fitting would be ‘Made of lead or lead alloy’.  

The third line of argument: The primary purpose of the GSIUR 1998 Regulations are to prevent danger to any person which includes the Gas Engineer doing the work. The instrument focus is on SAFETY so any materials like solder alloy used in gas engineering for making joints has to be safe to the public and persons working with the material.

Therefore, owing to the toxicity of lead to humans, the use of lead solder is in contravention of 5.(3) of GSIUR 1998 which states “No person shall carry out any work in relation to a gas fitting or gas storage otherwise than in accordance with appropriate standards and in such a way as to prevent danger to any person”.

To support this third line of argument presents the following reasoning – Lead is included on the EU REACH candidate list due to its reprotoxic properties and the UK is subject to these EU Chemical standards. Lead is used in welding and soldering products like lead alloy solder traditionally used for jointing gas pipes in the UK. However, there is substantial evidence that lead can cause damage to the nervous system. The World Health Organisation (WHO) has classified lead as one of ten chemicals of major public health concern which are “highly hazardous and can negatively affect our health and environment when improperly managed” (see here):

World Health Organisation recognise the danger of Lead to Human Health

WHO describe the key facts on Lead (see here):

  • Lead is a cumulative toxicant that affect multiple body systems and is particularly harmful to young children.
  • Lead in the body is distributed to the brain, liver, kidney and bones. It is stored in the teeth and bones, where it accumulates over time. Human exposure is usually assessed through the measurement of lead in blood.
  • Lead in bone is released into blood during pregnancy and becomes a source of exposure to the developing fetus.
  • There is no known level of lead exposure that is considered safe.
  • Lead exposure is preventable.

The UK Health and Safety Executive state that Women of child bearing capacity are prohibited from using lead solder and females are not allowed to clean premises where lead solder is used extensively – young people under the age of 18 are also prohibited from using lead solder (see here).

People can become exposed to lead through occupational sources like soldering pipes with leaded solder and other environmental sources from:

  • inhalation of lead particles generated by burning materials containing lead, for example, during smelting, lead soldering copper gas pipes, recycling, stripping leaded paint, and using leaded gasoline or leaded aviation fuel; and
  • ingestion of lead-contaminated dust from lead soldered gas pipes – especially when cleaned with wire wool, water (from leaded pipes), and food (from lead-glazed or lead-soldered containers). (my comments in bold)


In accordance with the purpose of the GIUSR (1998), for which the purpose is SAFETY, the legislation exists to protect persons from hazards to health – the evidence presented against the use of lead solder alloy on gas pipes and fittings is irrefutable – Therefore, lead solder use on gas distribution pipes is not allowed and if lead solder alloy is used, it presents a significant hazard to persons especially to women and children. 

Thus, lead solder must not be used on gas pipes and fittings in 2019 especially when lead-free options are inexpensive and readily available look forward to a written response from CIPHE and from readers who are free to comment on this article. 

Author: Dr Simon Reddy